Trap Distribution and Breakdown Characteristics of Direct-Fluorinated PI Film for DC-HTSFCL
High-temperature superconducting fault current limiter (HTSFCL) is an important application in the power industry. In high-voltage dc system, a polyimide (PI) is used as superconducting winding insulation in HTSFCL also withstands pulse voltage of lightning and operating voltage caused by line fault...
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Published in | IEEE transactions on applied superconductivity Vol. 29; no. 2; pp. 1 - 4 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
New York
IEEE
01.03.2019
The Institute of Electrical and Electronics Engineers, Inc. (IEEE) |
Subjects | |
Online Access | Get full text |
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Summary: | High-temperature superconducting fault current limiter (HTSFCL) is an important application in the power industry. In high-voltage dc system, a polyimide (PI) is used as superconducting winding insulation in HTSFCL also withstands pulse voltage of lightning and operating voltage caused by line fault and switching. The combined dc-pulse voltage makes the electric field more deformed, which induces partial discharge and accelerates insulation failure. Direct fluorination is a good means of regulating the molecular structure and electrical properties of polymers. This paper studies the trap distribution and breakdown characteristics of direct-fluorinated PI film. The corona charging was implemented in an environment with a relative humidity of 40%, using a combined dc-pulse voltage. To calculate the trap distribution, the surface potential was obtained. The breakdown voltage was also measured in LN 2 under different voltages. The experimental results indicate that moderate fluorination can effectively reduce the depth of trap level, accelerate charge detrapping, and improve the breakdown voltage of the PI film. |
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ISSN: | 1051-8223 1558-2515 |
DOI: | 10.1109/TASC.2019.2895098 |